Figure 4

(A) Abrogation of SIRT1 and CPT1 induction upon fasting by Gna12 KO. Immunoblottings for SIRT1 and CPT1 were performed and quantified on the liver homogenates from 12-week-old mice fed ad libitum, followed by fasting and refeeding for 24 hours (n = 4–5/group). (B) qRT-PCR assays for Acadl and Acadm in the liver (n = 5/group). (C) Effect of hepatic Gα12 gene knockdown on fasting induction of SIRT1. Immunoblottings for SIRT1 and CPT1 (center) in the liver homogenates and SIRT1 quantification (far right). Mice at 8 weeks of age were subjected to hydrodynamic injection with the plasmid-expressing sh-Gα12 or control (sh-Luci) (n = 4–6/group) (left). Third panel shows qRT-PCR assay for Gna12 in the liver (n = 4/group). (D) Representative H&E staining (left) and hepatic TG contents (right) from the same mice as in C (n = 4–6/group). Scale bars: 100 μm. (E) Effect of hepatocyte-specific Gα12 overexpression on fasting induction of SIRT1. Eight-week-old WT or Gna12-KO mice were injected with Lv-Gα12alb (or control) via the tail vein (left). Immunoblottings for SIRT1 and CPT1 were done on the liver homogenates (center) and SIRT1 quantification (right). Mice were subjected to fasting as in A. (n = 4/group). Third panel shows qRT-PCR assay for Gna12 in the liver (n = 7–10/group). (F) Representative H&E staining (left) and hepatic TG contents (right) from mice as described in E (n = 4–6/group). For E and F, only fasted groups were analyzed for ease of data presentation. Scale bars: 100 μm. Values represent mean ± SEM. Data were analyzed by 2-tailed Student’s t test (C and E, mRNA levels) or ANOVA followed by LSD (A and D) or Bonferroni’s (B, C, E, and F) post hoc tests. For A as well as C and E (protein levels), the blots in each panel were run in parallel using the same samples and β-actin was used as a normalization control for densitometric analysis.